Aspect ratio trapping (ART) technology has been used widely. In ART technology, if the epitaxy is performed at the later process of the manufacturing processes, it is hard to well-control long direction's defect along trenches formed by the manufacturing processes. In another condition, if the epitaxy is performed at the former process of the manufacturing processes, the epitaxy will grow on the flat silicon (Si) surface, which is hard to well-control epitaxy defect.